A preposition is a word or group of words used before a noun or noun phrase. For example: To show direction, use: to , into , onto : I'm going to the store. You should come into the house, it's cold outside. Walk onto the grass, it's not wet anymore. To show time, use: in , at , and on: * Use " in " with parts of the day, months, years, and seasons. For example: She reads everyday in the evenings. It gets very cold in December. My brother is going to graduate from college in 2020. It gets really hot in the summer. * Use " at " with the time of day, noon, night, and midnight. For example: Our favorite show starts at nine o'clock. Let's have lunch at noon. We like to run and exercise at night. The dogs sleep at midnight. * Use " on " with days. For example: We play basketball on Fridays. They eat pasta for dinner on Tuesdays. School starts on Monday. To refer to extended time, use the prepositions: " since ", ...